TMS FNC TaskDialog - Custom Buttons are calculated incorrectly

"Custom buttons" are calculated incorrectly if the text content is too short.
(W10, 4k, 200%, tested with TMS FNC TaskDialog Demo)

Incorrect:

From five characters upwards, the calculation is correct:

Hi,

Thank you for reporting this. We were able to reproduce the issue and we applied an improvement. The next version will contain the necessary changes.